<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	<script type="text/javascript" src="js/jquery-1.8.3.min.js" ></script>
	</head>
	<body>
		
		
		
		<input type="text" name="a" id="a"/>
		<input type="button" id="b" value="tijiao" onclick="bb()" />
		
		<script>
		function bb(){
			 var a=$("#a").val();
			 alert(a);
			
		}
		
		
	</script>
		
	</body>
	
</html>
